After attending a church service in Brooklyn Sunday, the Democratic mayoral candidate suggested Republicans don’t care about the city and criticized his GOP challenger for sticking with the party.

“I don’t understand, in this day and age, how someone could continue to be a Republican and say that they want to help New York City move forward,” de Blasio said of Joe Lhota outside Concord Baptist Church in Bedford-Stuyvesant.

“Republicans like him should have long ago fought back against negative trends in their party. He should have considered leaving the Republican Party.”

Last week it was de Blasio who sounded like a Republican when he declared he is a “fiscal conservative” at a breakfast for business leaders. He soon walked back the comment and now calls himself a “fiscally responsible progressive.”

Republicans called him fiscally unfit.

“Being told you’re working against the interests of New York City by Bill de Blasio is like being called ugly by a toad,” said GOP Party spokesman David Laska, who attacked de Blasio’s plan to raise taxes on the wealthy to pay for universal pre-K — a program that would costs less than 1% of the city budget.

“If he can’t come up with that money without raising taxes, he is unfit to manage a Starbucks, let alone New York City,” Laska said. Lhota, a former deputy mayor and budget director, said he can find the money without raising income taxes.

Lhota, meanwhile, attacked de Blasio’s education policy — ripping the notion that de Blasio want to improve educational opportunities for students while making it harder for charter schools to operate. De Blasio has suggested rent to charters, which serve a large population of minority students.

“Charter schools are working and we should be expanding school choice for parents, not limiting it,” Lhota said. “There is no way he can be concerned about breaking the cycle of poverty while being opposed to charter schools.”